Bug 41600: Add a tor circuit display panel.

browser/base/content/browser-init.js

browser/base/content/browser.js

browser/base/content/browser.js.globals

browser/base/content/browser.xhtml

browser/base/content/main-popupset.inc.xhtml

browser/base/content/navigator-toolbox.inc.xhtml

browser/components/moz.build

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1e8.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1e9.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1ea.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1eb.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1ec.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1ee.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f1.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f2.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f4.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f6.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f7.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f8.svg

...ents/torcircuit/content/tor-circuit-flags/1f1e6-1f1f9.svg